Got Mill Alignment Problems?

This episode on Blondihacks, I talk about sources of error in a milling machine! Exclusive videos, drawings, models & plans available on Patreon!

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[Blondihacks]

Hey everyone. I’m going to explain this further here, since it’s a VERY common comment that I’m distorting the part with the vise. That is not the case, but perhaps that section of the video isn’t sufficiently clear. This is 3/8” wall extrusion and I’m clamping it lightly for these tests. It is NOT distorting the part. Near the end I check for that by putting the DTI on the top, above the wall of the extrusion. It moves 15 thou. That’s a huge amount, and not in the middle where distortion would show. The part is moving, not distorting. It is ROLLING upwards on the round bar, which is why removing that eliminates the problem. I hope that clears it up.

[eatenkate]

My new favorite thriller genre: Investigative Machining

[StefanGotteswinter]

Isnt machine geometry fun? :D
Good investigation!

[britishreaction]

That was extremely interesting. Didn't see it coming. Well done for the methodical approach to fault finding that issue. That is another of your videos that I will be using as reference material in the future.

[RonCovell]

Quinn - what a great video. You have a special knack for concisely explaining nuanced technical information, while moving at a good pace, and keeping it fun!

[jimphubar]

Well, that's all cleared up. Just need a mill now..

[jeremybaker]

Love your channel, I hate it when my Cutter gets catty Wompus, but doesn’t everyone, thankful there’s a woman’s presence in the machining world, wish there were more. Grace and Peace!

[OldtimeIronman]

eh, shim PS did you see Stefan Gotteswinters video on shimming his mill with epoxy? Advantage, because it covers such a huge area and a fluid levels itself.

[noisytim]

I've got 99 problems - and this absolutely is one!

[cellularmitosis]

Watching you debug this problem is such a fantastic way to instruct folks on the process of machining!

[RichieRichOverdrive]

I've found my fair share of tram issues with flycutters. Most of the mills at my school hadn't been trammed since they arrived there, so when I had a back cut that looked like .010"-.015", I got a little suspicious. I ended up tramming most of the mills there. Good for practice, I suppose.

[hairyfro]

Regarding shimming the column, Stefan Gotteswinter has a great video where he shims it with annealed copper and fills the gap with a metal-filled epoxy material.

Interesting video as always!

[stanmacdonald]

Sounds like it's time for FEA! Looking at the side view of your setup, all the clamping force is through the rod some distance above the floor of the part. This will deflect the floor and the ceiling up on the rod side and tilt the top of the walls aft. The back jaw will resist this somewhat the back wall will deflect above the vise. If you move the rod to close to the middle of the floor I suspect the deflection will be greatly reduced.
Fusion 360 has FEA capabilities and it might be fun to see if you can approximate the results in sims. Wait, this is a machining channel!

[DonDegidio]

Hi Quinn,
I've always been a little leery of wall strength in aluminum extrusions when clamped. I square up the ends and clamp along that axis.

[michaelmechex]

That looked like an extremely painful and infuriating process. I would probably punch the machine from sheer anger and break my knuckles doing so. Anyway, I totally admire how calm you seem to be about it.

[hmw-mstx]

Oh no, it’s Devo. I went through all of this with my first mill which was a mill-drill, otherwise known as a glorified drill press. I was trying to shim the column in two planes at the same time. It was a long, frustrating process that resulted in some improvement. The best part of it was an opportunity to practice logical thinking and patience.

[userwl]

With the 2" cutter... loosen the bolts bring the tool to touch the bed or ground flat stock. Slowly tighten all the bolts. I promise it works. The simplest way. I do it almost every week after tilting the turret on a Bridgeport. Excellent video.

[TCB]

Great investigation and analysis. Thanks for sharing this!

[Rickmakes]

Great video! I come from woodworking. Another thing to do early on is check your square for square.

[andrewwilson]

Aluminium extrusions are seldom normalised and have a lot of internal stresses post manufacture. They pretty much settle into some form of equilibrium but this all goes to rats when you cut the skin on a surface. The stresses are unbalanced and it distorts. The degree of distortion depends on the quality of the extrusion. Ask for normalised extrusion or carry the process out yourself. This lesson was painfully learned machining alloy extrusions to make a large scale 3D printer ( 1.5 m x 1 m x 1m!)
Check the certificate of conformity for your stock, sure you got a good idea of what to avoid or at least treat with